From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757106Ab3BJW0Y (ORCPT ); Sun, 10 Feb 2013 17:26:24 -0500 Received: from mail.skyhub.de ([78.46.96.112]:60554 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756765Ab3BJW0W (ORCPT ); Sun, 10 Feb 2013 17:26:22 -0500 Date: Sun, 10 Feb 2013 23:26:18 +0100 From: Borislav Petkov To: Len Brown Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Len Brown , x86@kernel.org, "H. Peter Anvin" Subject: Re: [PATCH 2/2 v2] x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag Message-ID: <20130210222618.GA2573@pd.tnic> Mail-Followup-To: Borislav Petkov , Len Brown , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Len Brown , x86@kernel.org, "H. Peter Anvin" References: <1360483829-16349-1-git-send-email-lenb@kernel.org> <51181317.1080905@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <51181317.1080905@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 10, 2013 at 04:37:27PM -0500, Len Brown wrote: > From: Len Brown > > Remove 32-bit x86 a cmdline param "no-hlt", > and the cpuinfo_x86.hlt_works_ok that it sets. > > If a user wants to avoid HLT, then "idle=poll" > is much more useful, as it avoids invocation of HLT > in idle, while "no-hlt" failed to do so. > > Indeed, hlt_works_ok was consulted in only 3 places. > > First, in /proc/cpuinfo where "hlt_bug yes" > would be printed if and only if the user booted > the system with "no-hlt" -- as there was no other code > to set that flag. > > Second, check_hlt() would not invoke halt() if "no-hlt" > were on the cmdline. > > Third, it was consulted in stop_this_cpu(), which is invoked > by native_machine_halt()/reboot_interrupt()/smp_stop_nmi_callback() -- > all cases where the machine is being shutdown/reset. > The flag was not consulted in the more frequently invoked > play_dead()/hlt_play_dead() used in processor offline and suspend. > > Since Linux-3.0 there has been a run-time notice upon "no-hlt" invocations > indicating that it would be removed in 2012. > > Signed-off-by: Len Brown > Cc: x86@kernel.org > --- > v2: remove also check_hlt() [ … ] > diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c > index 3286a92..e280253 100644 > --- a/arch/x86/kernel/cpu/proc.c > +++ b/arch/x86/kernel/cpu/proc.c > @@ -28,7 +28,6 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c) > { > seq_printf(m, > "fdiv_bug\t: %s\n" > - "hlt_bug\t\t: %s\n" Are we fine with changing /proc/cpuinfo output? We tend to consider it an API to userspace, judging by past experience... -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --